Determination of the Dynamic Fracture Initiation Toughness of Metal-Ceramic Composites

The dynamic fracture of metals and metal-ceramic composites is investigated using three-point bend specimens subjected to dynamic loading. The specific material investigated is a metal-ceramic composite consisting of A359 aluminum reinforced by SiC particles. Three distinct approaches - a laser-based interferometric strain/displacement gage (ISDG), a resistance strain gage, and an experimental-numerical hybrid method - have been implemented to determine the dynamic stress intensity factor within a small pre-cracked three-point bend specimen. The specimen is impulsively loaded within a Kolsky bar type configuration, using an input bar and an output tube. The dynamic initiation fracture toughness of the material is obtained indirectly from these methods. The estimates of dynamic fracture initiation toughness determined from these three approaches are compared with each other and with quasistatic data.